JP2008539756A - Inkjet printing system - Google Patents

Abstract

A system for printing on an edible substrate includes an inkjet printer and a jetting fluid. The fluid is suitable for use on an edible substrate, and has a desirable viscosity and surface tension.

Description

Explanation of related applications

  This application claims priority from US Provisional Patent Application No. 60/679401, filed May 9, 2005. The contents of the specification of this patent application are hereby incorporated by reference in their entirety.

  The present invention relates to jet injection systems.

  Ink jet printers generally have an ink path from an ink reservoir to a nozzle path. The nozzle path terminates at a nozzle opening from which ink drops are ejected. Ink drop ejection is controlled in the ink path by pressurizing the ink with an actuator, which can be, for example, a piezoelectric deflecting element, a thermal bubble jet (registered trademark) generating element or an electrostatic deflecting element. A typical printhead has an array of ink paths with corresponding nozzle openings and associated actuators so that drop ejection from each nozzle opening can be controlled independently. In drop-on-demand printheads, each actuator is activated to selectively eject droplets at specific pixel locations in the image as the printhead and print substrate move relative to each other. It is done. In high performance printheads, the nozzle openings are generally 50 μm or smaller in diameter, for example on the order of 35 μm, separated by a pitch of 100-300 nozzles / inch (about 4-12 nozzles / mm), and 100-3000 dpi. It has a resolution (about 4-120 dots / mm) or higher, giving a droplet size of about 1-70 picoliters or less. The number of droplet ejection cycles is generally 10 kHz or higher.

  Integrated piezoelectric ink jet printing devices are described in US Pat. The contents of each patent document are hereby incorporated by reference in their entirety.

Sometimes it is desirable to print on food. An edible ink for a piezoelectric inkjet printer is described in US Pat. The contents of this patent document are hereby incorporated by reference in their entirety.
US Pat. No. 5,265,315 US Pat. No. 4,825,227 US Pat. No. 4,937,598 US Pat. No. 5,659,346 US Pat. No. 5,757,391 US Patent Application Publication No. 2004/0004649 International Publication No. 03/048260 Pamphlet

  An object of the present invention is to provide an ink jet printing means for printing on an edible substrate.

  The present invention relates to a jet injection system for printing on edible substrates.

  In one aspect, the invention features a system for printing on an edible substrate. The system comprises a liquid comprising a high cycle number piezoelectric ink jet printer for jetting at a cycle number of 10 kHz or higher and a surfactant for printing on an edible substrate, the liquid comprising about 20 Preferably, it has a surface tension of dynes / cm to about 40 dynes / cm. The edible substrate remains edible after printing with this liquid.

  In another aspect, the present invention is a method of printing on an edible substrate, the method comprising providing an inkjet printer, obtaining a precursor liquid having a surface tension greater than about 36 dynes / cm, a low surface suitable for application to the substrate. Adding a sufficient amount of surfactant to reduce the surface tension of the liquid by at least 10% to obtain a tension liquid and jetting the liquid onto the edible substrate, the edible substrate being edible after printing Features a method that remains.

  In another aspect, the invention features a system for printing on an edible substrate. The system has a piezoelectric ink jet printer configured to jet at a cycle number of 10 kHz or higher and a liquid for printing on an edible substrate. The liquid includes a surfactant that includes polysiloxane and has a surface tension of about 20 dynes / cm to about 40 dynes / cm. The edible substrate remains edible after printing with the liquid.

  In another aspect, the invention features a method of printing on an edible substrate. The method includes providing an inkjet printer, obtaining a precursor liquid having a surface tension greater than about 36 dynes / cm, and reducing the surface tension by at least 10% to obtain a low surface tension liquid suitable for application to an edible substrate. Adding a sufficient amount of a surfactant containing polysiloxane to the precursor liquid and jetting a low surface tension liquid onto the edible substrate, the edible substrate remaining edible after printing.

  Embodiments can have one or more of the following. The surface tension is from about 26 dynes / cm to about 36 dynes / cm, for example from about 28 dynes / cm to about 32 dynes / cm. The viscosity of the liquid is about 5 cP (centipoise) to 25 cP, for example, 10 cP to 14 cP. The liquid is substantially aqueous. The surfactant is ether-modified polydimethylsiloxane, polydimethylsiloxane, lecithin, lecithin derivative, phospholipid, glycerol ester, amphoteric amino acid, amphoteric imino acid, sorbitol, sorbitan, glycol ester, ester-modified polydimethylsiloxane or a mixture thereof. is there. The concentration of surfactant in the liquid is from about 2 g / liter to about 40 g / liter. The ink jet print head has a pumping chamber, and at least a part of the pumping chamber is formed of metal, carbon, or silicon. The print head has a nozzle opening. The nozzle opening is defined in metal, carbon or silicon. The print head has a nozzle opening of about 50 μm or smaller. The printhead resolution is 100 dpi or higher. The print head operates at a jet firing temperature of about 50 ° C. or higher. The system has a degassing rung.

  In another aspect, the invention features a liquid for use in a system for printing on an edible substrate that contains a surfactant, such as an ether-modified polydimethylsiloxane.

  Embodiments and / or aspects may have one or more of the following advantages. For printing on edible substrates, liquid compositions can be used that allow for the marking and marking of such substrates. Such markings can please and / or entertain consumers. In particular, printing on edible substrates can be fun and educational for children. This composition can improve the print accuracy of printheads by improving the uniformity of the size and velocity of droplets ejected from such printheads. This composition can also allow higher droplet ejection cycles, which can improve the resolution of ejected droplets by reducing bubbles in the pumping chamber.

  Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent application specifications, patent specifications, and other references cited herein are hereby incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

  Other features and advantages of the present invention will be apparent from the detailed description that follows.

  Referring to FIGS. 1-3, a system 10 for printing on food includes a piezoelectric print module 14, a jetting liquid 16 held in an ink reservoir 18, and an edible substrate 12 under the print module 14. An assembled substrate transport device 15 is provided for movement. The jet injection liquid 16 is formulated with the print module 14 to enhance reliable printing on the edible substrate 12. Specifically, the print module is a high cycle number jet injection module and the jet injection liquid has a selected surface tension and viscosity and is suitable for use with an edible substrate.

With particular reference to FIGS. 2 and 3, the inkjet printhead 20 has a plurality of flow passages each having an injection orifice 24 defined by a pump chamber 22 and an orifice plate 25. The jet injection liquid 16 from the tank is pressurized in the pump chamber 22 by the piezoelectric element 26 to form droplets that are ejected toward the substrate 12. The number of droplet ejection cycles is generally 10 kHz or higher, for example 20-30 kHz. The flow path is defined by a component formed of carbon, such as a pump chamber, and a component formed of metal, such as an orifice plate made of stainless steel, for example. A particular inkjet printhead is a Spectra Nova-AAA jet injection print module available from Spectra, Inc. of Hanover, New Hampshire, USA, with 256 independently-operable jets capable of operating up to 600 dpi. is there. This print module has the characteristics shown in the table below.

  The system can comprise a defoaming rung. Defoaming rungs are described in US Pat. No. 5,489,925. The contents of this patent specification are hereby incorporated by reference in their entirety.

  The jetting liquid is jetted in the form of a constant drop having a predictable volume, trajectory, shape and drop velocity, and such jetting is maintained over a range of printing conditions. Jet injection liquids are suitable for use with edible substrates and have surface tension and viscosity that enhance jet injection quality. The surface tension is such a surface tension that the jetting liquid effectively wets the liquid contact surfaces of the modules such as the pump chamber and the nozzle plate. Proper wetting promotes droplet formation and at the same time reduces the inhalation of air into the chamber and increases the efficiency of the defoaming rung. Viscosity is such that under jet injection conditions, liquid flow effectively spreads across a wet surface under variable pressure conditions caused by the module.

  In certain embodiments, the jetting liquid is a commercially available, substantially aqueous food grade liquid modified with a surfactant that can be used with an edible substrate. Specifically, the modified liquid has a surface tension of about 20 dynes / cm to about 40 dynes / cm. In certain embodiments, the liquid has a surface tension of about 26 dynes / cm to about 36 dynes / cm, such as about 28 dynes / cm to about 32 dynes / cm. Surface tension is measured using the De Nouy method. The Dunui method can be performed using, for example, a Sigma KSV 703 tensiometer available from KSV Instruments. The viscosity of the liquid is, for example, about 5 cP (centipoise) to about 25 cP at room temperature, for example, about 10 cP to about 14 cP. Viscosity is measured according to ASTM D2196 using a rotating cylinder viscometer. A suitable instrument is a Model DV-III programmable rheometer with a Thermoset System three sample holder controlled by a Model 106 programmable temperature controller available from Brookfield, Middleboro, Mass., USA. Using a # 18 spindle and at 60 rpm, the system can measure viscosities up to about 49.9 cP. Higher viscosities can be measured with a parallel plate viscometer. All surface tension and viscosity measurements are made at jet injection temperatures, eg 50-55 ° C.

  Surfactants include ionic surfactants such as cationic, anionic or amphoteric surfactants and nonionic surfactants. Exemplary surfactants include polysiloxanes such as ether-modified or polyether-modified polydimethylsiloxane, hydroxy functional polydimethylsiloxane, ester-modified or polyester-modified polydimethylsiloxane, polydimethylsiloxane, octamethylcyclotetrasiloxane, phenylsiloxane , Dimethicone, silsesquioxane, eg fully condensed or semi-condensed silsesquioxane, silicone wax, alkylmethylsiloxane, dimethicone copolyol, lecithin, lecithin derivative, phospholipid, glycerol ester, amphoteric amino acid, amphoteric imino acid, sorbitol Sorbitan, glycol ester, or a mixture of these surfactants.

Silsesquioxanes include fully condensed silsesquioxanes, semi-condensed silsesquioxanes, and polymerized silsesquioxanes. For example, the complete condensation silsesquioxanes, 1,3,5,7,9,11,13,15- octakis - (dimethylsiloxy) - pentacyclo - [9.5.1.1 ^3,9 .1 ^5,15 .1 ^7,13] oct siloxane and 1- (2-trans - cyclohexanediol) ethyl -3,5,7,9,11,13,15- isobutyl penta cyclo - [9.5.1.1 ^3,9 .1 ^5,15. 1 ^7,13 ] There is ^octasiloxane . Semi-condensed silsesquioxanes include 1,3,5,7,9,11,14-heptacyclopentyl-tricyclo- [7.3.3.1 ^5,11 ] heptasiloxane-endo-3,7,14-triol and 1 , 3,5,7,9,11-octacyclopentyl-tetracyclo- [7.3.3.1 ^5,11 ] octasiloxane-endo-3,7-diol. An example of a polymerized silsesquioxane is poly [(propyl methacryl-heptaisobutyl-PSS) -co- (n-butyl methacrylate)]. Other surfactants include polyoxyethylenated alkylphenols (mostly p-octyl, p-nonyl, p-dodecyl, dinonylphenol), polyoxyethylenated linear alcohol, polyoxyethylenated polyoxypropylene glycol, Polyoxyethylenated mercaptans, long-chain carboxylic acid esters (natural fatty acid glycerin and polyglycerin esters, propylene glycol, sorbitol and polyoxyethylenated sorbitol esters, polyoxyethylene glycol esters), alkanolamines (diethanolamine-, isopropanolamine-fatty acids Condensate), and alcohol, citric acid, succinic acid, diacetyl tartaric acid ester, monoglyceride and diglyceride, lactic acid ester, acetic acid ester, citric acid ester, Succinic acid ester, sorbitan ester, sucrose ester, poly (ethylene oxide), poly (propylene oxide), co-condensation polymer of ethylene oxide and polypropylene oxide, sodium lauryl sulfate, polysorbic acid esters 60 and 80, methylglycoside-coconut oil ester or their interface There is a mixture of active agents.

  Polysiloxane is available from Noveon, under the trade name UTRASIL ™, and from Dow Corning ™ and Struktol Company of America. In particular, ether-modified polydimethylsiloxane is available, for example, BYK33 from BYK Chemie. Silsesquioxane is available from Ardrich Chemical or Reade Advanced Materials. The construction of silsesquioxane and its reaction chemistry is described in “Silsesquioxanes, Bridging the Gap Between Polymers and Ceramics”, Ckemfiles, 2001, Vol. 1, Vol. 6 and generally discussed in Ardrich Chemical Company. The entire contents of this document are included herein by reference. Useful surfactants are generally recognized as safe as food additives directly under Article 21 of the US Federal Regulations Act, or surfactants are listed on the EAFUS list, ie, “ All added to food in the United States "list. Other useful surfactants are those that could be listed.

  Jet injection liquids can be made by adding a sufficient amount of the above listed surfactants to a precursor liquid, such as a base ink. A suitable base material liquid is the 'FG' series ink sold by Sensient / Formulabs of Escondido, California. The ink is composed of propylene glycol, glycerin, pure water, isopropyl alcohol, and an organic dye in descending order. The blue ink contains food blue No. 1 and food red No. 3. The red ink contains food red No. 3, food red No. 40 and food blue No. 1. The yellow ink contains food yellow No. 5, food red No. 50 and food blue No. 1. The green ink contains food yellow No. 5 and food blue No. 1, and also contains sodium hydroxide. These inks are 2.1%, 2-3%, 2.0% and 2.0% or more of the pure dye, respectively. In an embodiment, the jetting liquid is made by adding a sufficient amount of any of the listed surfactants to a base ink having a surface tension greater than about 36 dynes / cm. In order to obtain a low surface tension liquid suitable for application to the substrate with a sufficient amount of the selected surfactant, the surface tension of the liquid is at least 10%, such as 12%, 15%, 20%, 25%, Added to the precursor liquid to lower by 50% or more, for example 75%. The surfactant is selected such that the edible substrate remains edible after application of the liquid. In some embodiments, the surfactant has a surfactant concentration in the liquid of about 2 g / liter to about 40 g / liter, such as 5 g / liter, 10 g / liter, 20 g / liter or higher, such as Added to the matrix liquid to be 35 g / liter. In certain embodiments, the ether-modified polydimethylsiloxane is added at about 0.1 wt% to about 1 wt%, such as about 0.5 wt%.

  The liquid can contain, for example, from about 1% to about 20% by weight of water. The liquid can optionally contain a solid suspended in the liquid. For example, the solid can be titanium dioxide, silica, a pigment, such as a lake pigment, or a mixture of these solids. In some embodiments, the average particle size of the solid in the liquid is from about 0.05 μm to about 3 μm, such as 0.1 μm, 0.25 μm, 1 μm, or greater, such as 2.5 μm. The solid can comprise from about 1% to about 30% by weight of the liquid. The liquid can contain a wetting agent, for example, to prevent premature drying. For example, the wetting agent can be polyethylene glycol, polypropylene glycol, carbohydrate, polyol, sorbitol, polyacrylic acid or a mixture of these materials. The liquid can contain, for example, from about 5% to about 80% by weight of a wetting agent. The liquid can further contain a viscosity increasing agent or a thickening agent. For example, the thickening agent can be a polymer, salt, such as a lithium salt, or a mixture of salt and polymer. In certain embodiments, the thickening agent is propylene glycol alginate. The thickening agent can occupy the liquid, for example from about 1% to about 30% by weight. The liquid can contain a defoamer. For example, the defoamer can be polyethylene oxide, silicone oil, polydimethylsiloxane, polysorbate, sorbitan monostearate or aluminum stearate. The defoamer can comprise from about 1% to about 5% by weight of the liquid. The liquid can contain a biocide. For example, the biocide can be a paraben, an amino acid, a silver compound, such as a silver salt, such as silver nitrate, or a mixture of these biocides. The biocide can comprise from about 0.001% to about 1% by weight of the liquid. The liquid can contain a colorant. Suitable colorants include, for example, solids such as lake pigments, or soluble colorants such as food blue No. 1, food red No. 3, food red No. 40 and food yellow No. 5. In embodiments, the jetting liquid itself is not edible, but becomes edible after curing, for example after solvent evaporation.

  Ingredients suitable for edible materials are described in US Pat. The entire contents of this document are included herein by reference. Suitable seasonings include sugars or extracts such as fruit spice extracts. The material is listed as Generally Recognizes as Safe direct food additive (GRAS) in US Federal Regulations Article 21 or listed on the EAFUS list, ie, the United States Preferably, it contains edible ingredients which are included in the list of “everything added to food in the United States” of the Food and Drug Administration. An “edible material” is an ink that does not contain more than 100 ppm by weight of any impurities, ie, any ingredients not listed as GRAS or listed on the EAFUS list.

  Suitable substrates are fruits, chocolate, candy, chips or other food that can be consumed.

  A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.

  While a piezoelectric actuator has been described, other actuators are possible. For example, a thermal “bubble jet” actuator or an electrostatic deflection actuator can be used.

  Not limited to printing on a substrate, the jetting liquid of the present invention can be applied to an edible substrate to add flavor and / or aroma to the substrate.

FIG. 2 is a simplified perspective view of a printing apparatus having a printing module and an ink tank. It is a front perspective view of a print head. FIG. 3 is an enlarged perspective view of a part of the print head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 System 12 Edible substrate 14 Piezoelectric print module 15 Integrated substrate conveyance apparatus 16 Jet injection liquid 18 Ink tank 20 Inkjet print head

Claims (20)

In a system for printing on an edible substrate,
Piezoelectric inkjet printer configured to jet at 10 kHz or higher cycles, and a surfactant including polysiloxane, having a surface tension of 20 dynes / cm to about 40 dynes / cm Liquid for printing on an edible substrate,
Have
The system wherein the edible substrate remains edible after printing with the liquid.   The system of claim 1, wherein the surface tension is between 26 dynes / cm and 36 dynes / cm.   The system according to claim 1 or 2, wherein the surface tension is 28 dynes / cm to 32 dynes / cm.   The system according to claim 1, wherein the liquid has a viscosity of 5 cP to 25 cP.   The system of any one of claims 1 to 4, wherein the liquid has a viscosity of 10 cP to about 14 cP.   The system according to claim 1, wherein the liquid contains water.   The polysiloxane is ether-modified polydimethylsiloxane, polyether-modified polydimethylsiloxane, hydroxy-functional polydimethylsiloxane, ester-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, polydimethylsiloxane, octamethylcyclotetrasiloxane, phenylsiloxane, The system according to any one of claims 1 to 6, characterized in that it is selected from the group consisting of dimethicone, silsesquioxane, silicone wax, alkylmethylsiloxane, dimethicone copolyol and mixtures thereof.   The system according to any one of claims 1 to 7, wherein the polysiloxane comprises an ether-modified polydimethylsiloxane.   The system according to claim 1, wherein the concentration of the surfactant in the liquid is 2 g / liter to 40 g / liter.   The system according to claim 1, wherein the ink jet print head has a pump chamber, and at least a part of the pump chamber is made of metal, carbon, or silicon.   11. A system according to any one of the preceding claims, wherein the print head has nozzle openings, and the nozzle openings are defined in metal, carbon or silicon.   12. A system according to any one of the preceding claims, wherein the print head has a nozzle opening of 50 [mu] m or less.   13. A system according to any one of the preceding claims, wherein the print head has a resolution of 100 dpi or higher.   14. A system according to any preceding claim, wherein the print head operates at a jet firing temperature of 50 [deg.] C or higher. In a method of printing on an edible substrate, the method comprises:
Providing an inkjet printer;
Obtaining a precursor liquid having a surface tension greater than about 36 dynes / cm;
Adding a sufficient amount of a surfactant containing polysiloxane to the precursor liquid to reduce the surface tension by at least 10% to obtain a low surface tension liquid suitable for application to an edible substrate. The edible substrate remains edible after printing; and the step of jetting the low surface tension liquid onto the edible substrate;
A method comprising the steps of:   16. The method of claim 15, further comprising repeating the applying step until the surface tension of the liquid is between 28 dynes / cm and 32 dynes / cm.   The method of claim 15, wherein the surface tension is reduced by at least 25%.   The method according to claim 15, wherein the ink jet printer is a piezoelectric ink jet printer.   19. A method according to any one of claims 15 to 18, wherein the inkjet printer is configured to jet at a cycle number of about 10 kHz or higher.   20. A method according to any one of claims 15 to 19 wherein the polysiloxane comprises ether-modified polydimethylsiloxane.

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